UP2715K. Which Mac computers are supported?

Unknown. I sent an email to the displays team.

We are only going to test on the following for 4K support =
MacBook Pro Retina (Late 2013 and later)
MacBook Pro (Late 2013)
iMac 27" (Late 2013 and later)
Mac Mini (Late 2014)

No Ultra HD 5K 5120x2880 60Hz support =
The current DisplayPort 1.2 specification used over Thunderbolt 2 on apple's latest Macs simply isn't capable of handling the bandwidth necessary for 5K video over a single cable. As a result, no current Mac models that do support 4K displays, can currently drive a 5K external display. So you would have to use 3840x2160 30Hz.

Problem = UP2715K 5K display is not supported on apple
* Older apple do not support DP1.2
* Displaying 5K resolution on UP2715K requires 2x DP1.2 cable connection with DisplayID support
* The apple driver currently does not support 2x DP1.2 configuration with DisplayID

Discussion = Switch to 4K resolution
* System requirement: apple OS 10.10 or later
* Connect to monitor using a single DP to Mini-DP cable. The Mini-DP side should be connected to the monitor

So a late 2013 Mac Pro with 2 thunderbolt controllers isn't enough to support 5k? Granted it would be an AMD driver solution. This was a most depressing return for me. I do want to add what I've read on other sites regarding MacBook pros.....the two thunderbolt ports share a thunderbolt controller so they cannot act like two full thunderbolt(dp1.2) ports. However, the Mac Pro has 3 thunderbolt controllers with 6 ports so that should work.

A user has posted that using the UP2715K with the Mac Pro mini-desktop works at 5120x2880 60Hz using the two mDP one above the other setup.